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Gregor Mendel
Experiment: Bred garden peas, prevented self-polination, cross-fertilized, planted seeds, color of flower vs. pea seed, P generation to F1 generation (offspring.
Contribution: laws of segregation, dominant vs. recessive flowers, parents pass on their characteristics to F1, genotypes and phenotypes, pairs of genes segregate during gamete formation, the fusion of gamets at fertilization pairs genes once again. -
William Bateson and Reginald Punnett
Experiment: crossed flowers and used observed vs. expected results, produced recombinant genes
Contribution: discovered linked-genes (genes close together on chromosome), recombinant frequencies (the percent of ofspring different from parents -
Thomas Hunt Morgan
Experiment: used fruit flies, traced the inheritance of the traits, mated the flies, counted offspring, looked at traits, and compaired observed vs. expected (recombination frequency)
Contribution: Recombination frequency (the percent of recombinants/different from parents) -
Archibald Garrod
Experiment: hypothesised that normal individuals have an enzyme that breaks down alkapton
Contribution: genes dedicate phenotypes through enzymes, normal individuals have an enzyme to break down alkapton -
Frederick Griffith
Experiment- 1. S bacteria killed the mouse, 2. R bacteria don't kill mouse, 3. Heat killed S bacteria don't kill mouse, 4. Heat killed S bacteria and R bacteria killed the mouse.
Contribution: discovered transformation-change in the phenotype -
George Beadle and Edward Tatum
Experiment: took mold that was unable to grow normally and locked an enzyme
Contribution: each mutant is defective in a single gene, one gene-one enzyme, one polypeptide -
Erwin Chargaff
Experiment: double helix, A always paired with T, G always pairs with C
Contribution: Amount of Adenine in DNA=amount of Thymine, amount of Guanine= amount of Cytosine -
Alfred Hershey and Martha Chase
Experiment: 1.bacteriophage with only DNA and protein, 2. DNA tagged by radioactive phosphorus and protein with radioactive sulfur
Contribution: DNA is genetic material, DNA is a hereditary material -
Maurice Wilkins and Rosalind Franklin
Experiment: X-ray crystallographic photo of DNA, examined the photo and came to a conclusion
Contribution: Wilkins took Franklins picture and figured out that it's a helix -
James Watson and Francis Crick
Experiment" construct double helix-fail, construct with nitrogen base in specific order
Contribution: DNA is a double helix, diameter=2nm, nitrogen bases=.33 nm apart -
Marshall Nirenberg
Experiment: synthesized an artificial RNA molecule by linking together identical RNA nucleotides having uracil as their base
Contributions: codons-RNA and DNA in a series of 3-base woras, triplet code-genetic instructions for amino acid sequence of a polypeptide chain, triplet codon-UUU
